Zusammenfassung der Ressource
Schizo - Genetics
- Twin Studies
- more closely you re bio related to someone
with schizo, greater your prob of schizo is
- GOTTESMAN 1991
- MZ twins have higher concordat for
schizo than DZ twins
- MZ twins only have 50% not 100% concordance.
MZ twins could differ because gene activated in
over and suppressed in another or environment diff
- TSUJITA ET AL 1998
- greater similarity between DZ twins than siblings, DZ
twins have same genetic resemblance as siblings but
greater environment similarly incl. prenatal
- Adopted
Children Who
Develop
Schizophrenia
- adoptive children with schizo - common
in bio parents not adoptive
- children with a moderately high probability of schizo
even if adopted by mentally healthy parents
- suggests genetic basis but also consistent
with prenatal influence
- pregnant mothers pass genes and
provide prenatal environment for child
- many smoke, drink, drugs,
eat unhealthy during
pregnant
- they have a disproportionate number
complications during pregnancy and delivery
- study of adoptive children in finalnd found high probability of
schizo or related conditions among children who had a bio
mother with schizo
- genetic risk itself or disordered family had less effect
- WYNNE ET AL 2006
- Efforts to Locate a Gene
- more than dozen appear to be
more common in people with schizo
- DISC1 (disrupted in schizo 1)
- controls production of dendritic spines and
generation of new neurones in the hippo
- DUAN ET AL 2007
- other genes are important for
brain development
- control of transmission at
glutamate synapses
- connections between hippo
and prefrontal cortex
- haven't replicates any of these studies
- if schizo depended on a single gene it would
be hard to stay in 1% of population
- those with schizo die younger
than others
- fewer than half as many children
other people do
- many cases of schizo arise from new mutations
- mutations don't come around that often
- proper brain development depends
on hundreds of genes
- mutation in one gene is rare but mutation
in several hundred isn't
- more likely possibility is deletion of gene -
common error in reproduction
- examined chromosomes of people with
and without schizo
- found genetic micro deletions and micro duplications in 5%
control 15% schizo and 20% onset schizo before 18
- leads to hypothesis that new mutation or deletion of any of a large number
genes disrupts brain development and increase prob of schizo